Intelligent Digital Redesign for Nonlinear Interconnected Systems using Decentralized Fuzzy Control

Abstract

-In this paper, a novel intelligent digital redesign (IDR) technique is proposed for the nonlinear interconnected systems which can be represented by a Takagi-Sugeno (T-S) fuzzy model. The IDR technique is to convert a pre-designed analog controller into an equivalent digital one. To develop this method, the discretized models of the analog and digital closed-loop system with the decentralized controller are presented, respectively. Using these discretized models, the digital decentralized control gain is obtained to minimize the norm between the state variables of the analog and digital closed-loop systems and stabilize the digital closed-loop system. Its sufficient conditions are derived in terms of linear matrix inequalities (LMIs). Finally, a numerical example is provided to verify the effectiveness of the proposed technique.

Sampled-Data Observer-Based Decentralized Fuzzy Control for Nonlinear Large-Scale Systems

“…However, in the case of nonlinear systems, the exact discretization is not possible, and so, to overcome this problem, various nonlinear sampled-data control techniques have been proposed, such as the Euler approximation [8,9] and the conversion to an input delay controller [10,11]. Sampled-data fuzzy control techniques, which are combination of the sampled-data control technique and the T-S fuzzy model, have also been proposed in many studies [16][17][18][19][20][21][22][23][24][25][26][27] and are categorized into the input delay conversion approach and the direct discrete-time design approach.…”

“…However, there are few studies about observer-based control or decentralized control in the input delay conversion approach. The direct discrete-time design approach [20][21][22][23][24][25][26][27] is to guarantee stability using the discretized model of the continuous-time plant. In [20][21][22], various sampled-data fuzzy control techniques using the direct discrete-time design approach have been proposed, such as the observer-based outputfeedback scheme [20] and the robust control [21].…”